In the previous post, I gave you a list of some of the latest and best custom ROMs for the Samsung Galaxy S3. I also wrote a short installation method for different ROMs. While the advanced Galaxy S3 users can easily install the ROMs with the help of short instructions, those who are new to Android and the flashing business would naturally prefer to read a detailed tutorial before they install a custom ROM to their Samsung Galaxy S3. The present guide will help you install custom ROM on your Galaxy S3.
Please note that you will need to root your SGS3 before being able to install a custom ROM. One might ask: “Why should I go for a custom ROM? In fact, the reasons that draw an Android user towards custom ROMs are:
- Better battery life for the device
- The faster and smoother UI experience
- Total command over system files
- Integration of apps and features from other devices
- More free RAM and CPU
- An advanced user can further mod a custom ROM according to his taste.
- Innumerable other features…
Warning
All the privileges described above come with a little price: voiding the warranty of your device. Flashing/installing a custom ROM to your device might prove fatal for your phone if the instructions are not followed carefully. Though the method described here has been tried by millions of Android phone owners successfully, we do not guarantee that you will also be like those lucky millions. Follow the guide at your own responsibility.
Prerequisites before Flashing a Custom ROMs
- Download the desired custom ROM file and, if provided, the GApps (Google Apps) to your PC.
- Make sure that you have backed up the Contacts, Messages, Call Log entries, app settings, APN details, etc. You can download theme free apps directly from the Google Play Store. Additionally, you can use the Samsung Kies to backup your phone’s data on your PC. You can also sync your contacts via Gmail sync feature.
- Your device should be amply charged before flashing a custom ROM. It is not that the procedure is very long. It would take just a few minutes. Take it as a precaution in case anything goes wrong.
- Open Settings on your device and turn on USB Debugging: Settings> Developer Options> USB Debugging> Tick the box.
Steps to Install Custom ROM on Galaxy S3
If you have taken the measures described above, just follow the simple steps given below to install the ROM on to your Samsung Galaxy S3:
- Usually, all ROM file comes in a zip package. You must not extract the zip and copy the file as it is to the SD Card of your device by connecting it to PC via USB Cable. However, to make sure that the ROM file that you downloaded is complete and not broken, you can extract it. A corrupt zip file is never extracted completely. If you get an error message, the ROM file is not complete, and you will have to download it again.
- (Optional) Make sure to copy the GApps zip file (if provided) too to the SD Card of the device. It is named like this: “gapps-ics-20120429-signed.zip”. If the ROM developer has not suggested to download the GApps, skip these steps.
- Turn off your device and boot it into CWM Recovery mode: press and hold the Volume Up+Home (center) keys simultaneously and then press the Power button. Keep the three keys pressed till the StartUp screen with “Samsung Galaxy SIII” logo blinks for two times followed by a screen like this:
- In CWM Recovery mode, use volume, home, and power button to navigate and select an option. If your device has CWM Touch Recovery, you can do things either by touching an option or using the physical buttons.
- Having entered the CWM Recovery mode, go to “backup and restore> backup”, and create a backup of your current ROM. In case anything wrong happens during flashing the custom ROM, or you like to go back to the previous ROM/Firmware, you can restore it back from CWM Recovery later. (Must do it)
- Most custom ROMs need three wipes to be installed properly. You will have to do them all as directed below.
- In CWM main menu, select “wipe data/factory reset> yes”
- Then select “wipe cache partition> yes”
- Go to “advanced> wipe dalvik cache> yes”
- Now select “Go back” option to return to the main menu and opt “install zip from sdcard>choose zip from sdcard” and browse to the ROM file that you copied to the device in Step 1. Select “yes”.
- The CWM Recovery will now start flashing the ROM to your device. Wait till it completes.
- (Optional) Now come back to the main menu and select “install zip from sdcard>choose zip from sdcard” again. This time you will have to install the GApps package in zip.
- Finally, come back to the main menu and select “reboot system now’.
- It might take up to five minutes to reboot your device. Just wait patiently.
On reboot, your device might ask you to sign in to your Google account. Do it or skip it. Your device should now be running on the new custom ROM. Cheers!!! Enjoy the new ROM.
If you find any problem or have any doubts regarding the topic, do not hesitate to drop a comment.
Is there a way to install CWM in sd card. My port doesn’t detect data, it only charged and my phone was corrupted.
No, you can’t do that. TWRP is a recovery file that’s the integral past of the system.
Am on Stock rom now. From what I have read so far, if am flashing custom rom, I need to first root the device. Step 7 does the same ??
I am getting an error saying error in /emmc/0/ cm-11……(the rom I am trying to install) and (status 7) what could be thr problem?
Update your custom recovery and try again.
i am getting an error saying failed to mount cache? what is it
Go to Mounts and storage option and try mounting cache. Then try again.